Quantum Theories, Misc

The unreduced many-body interaction problem solution, absent in usual science framework, reveals a new quality of emerging multiple, equally real but mutually incompatible system configurations, or “realisations”, giving rise to the universal concept of dynamic complexity and chaoticity. Their imitation by a single, “average” realisation or trajectory in usual theory (corresponding to postulated “exact” or perturbative problem solutions) is a rough simplification of reality underlying all stagnating and emerging problems of conventional (unitary) science, often in the form of missing, or (...) “dark”, entities and “hidden variables”. We show how the application of unreduced interaction problem solution and the ensuing concept of dynamic complexity provides the desired causally complete and intrinsically unified solutions to respective unitary science problems in the entire range of complexity levels, from elementary particles and cosmology to emergent consciousness and modern development crisis, implying real, essential and urgently needed progress. (shrink)

Is the quantum state part of the furniture of the world? Einstein found such a position indigestible, but here I present a different understanding of the wavefunction that is easy to stomach. First, I develop the idea that the wavefunction is nomological in nature, showing how the quantum It or Bit debate gets subsumed by the corresponding It or Bit debate about laws of nature. Second, I motivate the nomological view by casting quantum mechanics in a “classical” formalism (Hamilton–Jacobi theory) (...) and classical mechanics in a “quantum” formalism (Koopman–von Neumann theory) and then comparing and contrasting classical and quantum wave functions. I argue that Humeans about laws can treat classical and quantum wave functions on a par and that doing so yields many benefits. (shrink)

In this article I raise a new problem for quantum mechanics, which I call the control problem. Like the measurement problem, the control problem places a fundamental constraint on quantum theories. The characteristic feature of the problem is its focus on state preparation. In particular, whereas the measurement problem turns on a premise about the completeness of the quantum state ('no hidden variables'), the control problem turns on a premise about our ability to prepare or control quantum states. After raising (...) the problem, I discuss some applications. I suggest that it provides a useful new lens through which to view existing theories or interpretations, in part because it draws attention to aspects of those theories that the measurement problem does not. I suggest that it also helps clarify the physical significance of the well-known no-go result—the no-cloning theorem—on which it is based. (shrink)

Quasi-set theory $\cal Q$ allows us to cope with certain collections of objects where the usual notion of identity is not applicable, in the sense that $x = x$ is not a formula, if $x$ is an arbitrary term. $\cal Q$ was partially motivated by the problem of non-individuality in quantum mechanics. In this paper I discuss the range of explanatory power of $\cal Q$ for quantum phenomena which demand some notion of indistinguishability among quantum objects. My main focus is (...) on the double-slit experiment, a major physical phenomenon which was never modeled from a quasi-set-theoretic point of view. The double-slit experiment strongly motivates the concept of degrees of indistinguishability within a field-theoretic approach, and that notion is simply missing in $\cal Q$. Nevertheless, other physical situations may eventually demand a revision on quasi-set theory axioms, if someone intends to use it in the quantum realm for the purpose of a clear discussion about non-individuality. I use this opportunity to suggest another way to cope with identity in quantum theories. (shrink)

Gregor Schiemann führt allgemeinverständlich in das Denken dieses Physikers ein. Thema sind die Erfahrungen und Überlegungen, die Heisenberg zu seinen theoretischen Erkenntnissen geführt haben, die wesentlichen Inhalte dieser Erkenntnisse sowie die Konsequenzen, die er daraus für die Geschichte der Physik und das wissenschaftliche Weltbild gezogen hat. Heisenbergs Vorstellungswelt durchzieht durch ein Spannungsverhältnis, das heute noch das Denken vieler Wissenschaftlerinnen und Wissenschaftler bewegt. Er ist um ein umfassendes Verständnis der Naturprozesse bemüht, zugleich aber von der Berechenbarkeit und Beherrschbarkeit von Phänomenen auch (...) dann schon fasziniert, wenn die zugrunde liegenden Prozesse erst teilweise verstanden sind. Aus der Geschichte der Physik zieht er die wirkungsreiche Lehre, daß sich die naturwissenschaftliche Erkenntnis nicht kontinuierlich, sondern sprunghaft in Form von Revolutionen entwickelt. Die Reichweite des physikalischen Wissens begrenzt er in einer Schichtentheorie der Welt, nach der die komplexen Phänomene des Lebens nicht allein durch die Wechselwirkungen zwischen ihren Bestandteilen erklärt werden können. Der zunehmenden Technisierung der Welt steht Heisenberg kritisch gegenüber. Seiner Zeit weit voraus, glaubt er, daß die Technisierung der Welt eine epochal neue Stufe erreicht habe, in der der Mensch „nur noch sich selbst“ gegenüberstehe. (shrink)

Feynman's sum-over-histories formulation of quantum mechanics has been considered a useful calculational tool in which virtual Feynman histories entering into a coherent quantum superposition cannot be individually measured. Here we show that sequential weak values, inferred by consecutive weak measurements of projectors, allow direct experimental probing of individual virtual Feynman histories, thereby revealing the exact nature of quantum interference of coherently superposed histories. Because the total sum of sequential weak values of multitime projection operators for a complete set of orthogonal (...) quantum histories is unity, complete sets of weak values could be interpreted in agreement with the standard quantum mechanical picture. We also elucidate the relationship between sequential weak values of quantum histories with different coarse graining in time and establish the incompatibility of weak values for nonorthogonal quantum histories in history Hilbert space. Bridging theory and experiment, the presented results may enhance our understanding of both weak values and quantum histories. (shrink)

The ’microcausality’ condition in quantum field theory is typically presented and justified on the basis of general principles of physical causality. I explore in detail a number of alternative causal interpretations of this condition. I conclude that none is fully satisfactory, independent of further and controversial assumptions about the object and scope of quantum field theories. In particular the stronger causalreadings require a fully reductionist and fundamentalist attitude to quantum field theory. I argue, in a deflationary spirit, for a reading (...) of the ‘microcausality’ condition as merely a boundary condition, inspired by Relativity, that different possible formulations of quantum field theory must obey. (shrink)

Instead of postulated fixed structures and abstract principles of usual positivistic science, the unreduced diversity of living world reality is consistently derived as dynamically emerging results of unreduced interaction process development, starting from its simplest configuration of two coupled homogeneous protofields. The dynamically multivalued, or complex and intrinsically chaotic, nature of these real interaction results extends dramatically the artificially reduced, dynamically single-valued projection of standard theory and solves its stagnating old and accumulating new problems, “mysteries” and “paradoxes” within the unified (...) and causally complete picture of intrinsically evolving, dynamically complex reality. The permanently unfolding complexity progress thus revealed is fundamentally unlimited and does not need to stop at the directly observed diversity of usual matter complexity. The exciting, but rigorously substantiated and objectively inevitable prospects of further civilisation complexity development towards its superior levels of genuine sustainability and global Noosphere are outlined, with practically important conclusions for today’s critical problem solution. (shrink)

We indicate a new way in the solution of the problem of the quantum measurement . In past papers we used the well-known formalism of the density matrix using an algebraic approach in a two states quantum spin system S, considering the particular case of three anticommuting elements. We demonstrated that, during the wave collapse, we have a transition from the standard Clifford algebra, structured in its space and metrics, to the new spatial structure of the Clifford dihedral algebra. This (...) structured geometric transition, which occurs during the interaction of the S system with the macroscopic measurement system M, causes the destruction of the interferential factors. In the present paper we construct a detailed model of the (S+M) interaction evidencing the particular role of the Time Ordering in the (S+M) coupling since we have a time asymmetric interaction . We demonstrate that , during the measurement , the physical circumstance that the fermion creation and annihilation operators of the S system must be destroyed during such interaction has a fundamental role . (shrink)

In this paper I investigate, within the framework of realistic interpretations of the wave function in nonrelativistic quantum mechanics, the mathematical and physical nature of the wave function. I argue against the view that mathematically the wave function is a two-component scalar field on configuration space. First, I review how this view makes quantum mechanics non- Galilei invariant and yields the wrong classical limit. Moreover, I argue that interpreting the wave function as a ray, in agreement many physicists, Galilei invariance (...) is preserved. In addition, I discuss how the wave function behaves more similarly to a gauge potential than to a field. Finally I show how this favors a nomological rather than an ontological view of the wave function. (shrink)

The paper is replaced by a new version (12-2019): DOI: 10.5281/zenodo.3572846 -/- Physical phenomena emerge from the quantum fields everywhere in space. However, not only the phenomena emerge from the quantum fields, the law of the conservation of energy must have its origin from the same spatial structure. This paper describes the relations between the main law of physics and the mathematical structure of the “aggregated” quantum fields.

A brief account of epistemological models that try to unfold the intertheoretic context of theory change is proposed. It is stated that all of them has a host of drawbacks, the most salient one being the lack of adequate description of the research traditions interaction process. The epistemological model of mature theory change, eliminating the drawback, is contemplated and illustrated.

This paper shows how the classical finite probability theory (with equiprobable outcomes) can be reinterpreted and recast as the quantum probability calculus of a pedagogical or toy model of quantum mechanics over sets (QM/sets). There have been several previous attempts to develop a quantum-like model with the base field of ℂ replaced by ℤ₂. Since there are no inner products on vector spaces over finite fields, the problem is to define the Dirac brackets and the probability calculus. The previous attempts (...) all required the brackets to take values in ℤ₂. But the usual QM brackets <ψ|ϕ> give the "overlap" between states ψ and ϕ, so for subsets S,T⊆U, the natural definition is <S|T>=|S∩T| (taking values in the natural numbers). This allows QM/sets to be developed with a full probability calculus that turns out to be a non-commutative extension of classical Laplace-Boole finite probability theory. The pedagogical model is illustrated by giving simple treatments of the indeterminacy principle, the double-slit experiment, Bell's Theorem, and identical particles in QM/Sets. A more technical appendix explains the mathematics behind carrying some vector space structures between QM over ℂ and QM/Sets over ℤ₂. (shrink)

In this paper I present the common structure of quantum theories with a primitive ontology, and discuss in what sense the classical world emerges from quantum theories as understood in this framework. In addition, I argue that the primitive ontology approach is better at answering this question than the rival wave function ontology approach or any other approach in which the classical world is nonreductively ‘emergent:’ even if the classical limit within this framework needs to be fully developed, the difficulties (...) are technical rather than conceptual, while this is not true for the alternatives. (shrink)

The operator structures for the constants of the motion of the relativistic hydrogen atom are examined. ThoughJ 3 andJ · J are constants of the motion,J is not. Its replacement, $\tilde {\rm K}$ , is shown to emerge rather naturally in transforming the equation to spherical coordinates. The separation of variables is presented in hypercomplex number form. This leads to some interesting suggestions regarding the matter/antimatter operator for the Dirac equation.

A cura di Ignazio Licata, Ammar J. Sakaji Jeffrey A. Barrett, Enrico Celeghini, Leonardo Chiatti, Maurizio Consoli, Davide Fiscaletti, Ervin Goldfain, Annick Lesne, Maria Paola Lombardo, Mohammad Mehrafarin, Ronald Mirman, Ulrich Mohrhoff, Renato Nobili, Farrin Payandeh, Eliano Pessa, L.I Petrova, Erasmo Recami, Giovanni Salesi, Francesco Maria Scarpa, Mohammad Vahid Takook, Giuseppe Vitiello This volume comes out from an informal discussion between friends and colleagues on the answer:what topic do you think as fundamental in theoretical physics nowadays? Obviously wereceived different answers (...) according to the disposition and the different research areas, and answersin superposition state too. And yet some attractors have emerged pointing out the keys forthe Physicists conception of Nature, all of them converging towards a group of stronglyinterconnectedproblems. Let's see them one by one:. The concept of particle identity in Quantum Mechanics (QM) and Quantum Field Theory (QFT);. The relationship between QM and QFT, in particular the non -local aspects in Field Theory andthe problem of non-perturbative solutions;. The local/global problem in the relationship between particle physics and cosmology;. The role of Renormalization group in describing the meso and macroscopic emergent behaviour;. The possible extension of Poincaré symmetry group and Quantum cosmology;. Higgs "mechanism" and the origin of mass. (shrink)

In this paper I outline my propensiton version of quantum theory (PQT). PQT is a fully micro-realistic version of quantum theory that provides us with a very natural possible solution to the fundamental wave/particle problem, and is free of the severe defects of orthodox quantum theory (OQT) as a result. PQT makes sense of the quantum world. PQT recovers all the empirical success of OQT and is, furthermore, empirically testable (although not as yet tested). I argue that Einstein almost put (...) forward this version of quantum theory in 1916/17 in his papers on spontaneous and induced radiative transitions, but retreated from doing so because he disliked the probabilistic character of the idea. Subsequently, the idea was overlooked because debates about quantum theory polarised into the Bohr/Heisenberg camp, which argued for the abandonment of realism and determinism, and the Einstein/Schrödinger camp, which argued for the retention of realism and determinism, no one, as a result, pursuing the most obvious option of retaining realism but abandoning determinism. It is this third, overlooked option that leads to PQT. PQT has implications for quantum field theory, the standard model, string theory, and cosmology. The really important point, however, is that it is experimentally testable. I indicate two experiments in principle capable of deciding between PQT and OQT. (shrink)

We review a recent approach to the foundations of quantum mechanics inspired by quantum information theory. The approach is based on a general framework, which allows one to address a large class of physical theories which share basic information-theoretic features. We first illustrate two very primitive features, expressed by the axioms of causality and purity-preservation, which are satisfied by both classical and quantum theory. We then discuss the axiom of purification, which expresses a strong version of the Conservation of Information (...) and captures the core of a vast number of protocols in quantum information. Purification is a highly non-classical feature and leads directly to the emergence of entanglement at the purely conceptual level, without any reference to the superposition principle. Supplemented by a few additional requirements, satisfied by classical and quantum theory, it provides a complete axiomatic characterization of quantum theory for finite dimensional systems. (shrink)

The aim of this paper is to summarize a particular approach of doing metaphysics through physics - the primitive ontology approach. The idea is that any fundamental physical theory has a well-defined architecture, to the foundation of which there is the primitive ontology, which represents matter. According to the framework provided by this approach when applied to quantum mechanics, the wave function is not suitable to represent matter. Rather, the wave function has a nomological character, given that its role in (...) the theory is to implement the law of evolution for the primitive ontology. (shrink)

It has been argued that the transition from classical to quantum mechanics is an example of a Kuhnian scientific revolution, in which there is a shift from the simple, intuitive, straightforward classical paradigm, to the quantum, convoluted, counterintuitive, amazing new quantum paradigm. In this paper, after having clarified what these quantum paradigms are supposed to be, I analyze whether they constitute a radical departure from the classical paradigm. Contrary to what is commonly maintained, I argue that, in addition to radical (...) quantum paradigms, there are also legitimate ways of understanding the quantum world that do not require any substantial change to the classical paradigm. (shrink)

In this paper, we discuss the general significance of order in physics, as a first step toward the development of new notions of order. We begin with a brief historical discussion of the notions of order underlying ancient Greek views, and then go on to show how these changed in key ways with the rise of classical physics. This leads to a broader view of the significance of order, which helps to indicate what is to be meant by a change (...) of our general notions of order in physics. We then go into relativity and quantum theory, showing how these developments actually did bring in further new notions of order, which are however inconsistent and otherwise inadequate in certain ways. Finally, using these inconsistencies and inadequacies as clues or indications for yet a further new concept of order, we make some proposals for novel directions of inquiry (to be discussed in some detail in later papers) which could lead to theories as different from relativity and quantum theory as these are from classical physics. (shrink)

The primary quantum mechanical equation of motion entails that measurements typically do not have determinate outcomes, but result in superpositions of all possible outcomes. Dynamical collapse theories (e.g. GRW) supplement this equation with a stochastic Gaussian collapse function, intended to collapse the superposition of outcomes into one outcome. But the Gaussian collapses are imperfect in a way that leaves the superpositions intact. This is the tails problem. There are several ways of making this problem more precise. But many authors dismiss (...) the problem without considering the more severe formulations. Here I distinguish four distinct tails problems. The first (bare tails problem) and second (structured tails problem) exist in the literature. I argue that while the first is a pseudo-problem, the second has not been adequately addressed. The third (multiverse tails problem) reformulates the second to account for recently discovered dynamical consequences of collapse. Finally the fourth (tails problem dilemma) shows that solving the third by replacing the Gaussian with a non-Gaussian collapse function introduces new conflict with relativity theory. (shrink)

A non-classical, non-quantum theory, or NCQ, is any fully consistent theory that differs fundamentally from both the corresponding classical and quantum theories, while exhibiting certain features common to both. Such theories are of interest for two primary reasons. Firstly, NCQs arise prominently in semi-classical approximation schemes. Their formal study may yield improved approximation techniques in the near-classical regime. More importantly for the purposes of this note, it may be possible for NCQs to reproduce quantum results over experimentally tested regimes while (...) having a well defined classical limit, and hence are viable alternative theories. We illustrate an NCQ by considering an explicit class of NCQ mechanics. Here this class will be arrived at via a natural generalization of classical mechanics formulated in terms of a probability density functional. (shrink)

The phase φ of any wave is determined by the ratio x/λ consisting of the distance x propagated by the wave and its wavelength λ. Hence, the dependence of φ on λ constitutes an analogue system for the mathematical operation of division, that is to obtain the hyperbolic function f(ξ)≡1/ξ. We take advantage of this observation to decompose integers into primes and implement this approach towards factorization of numbers in a multi-path Michelson interferometer. This work is part of a larger (...) program geared towards unraveling the connections between quantum mechanics and number theory. We briefly summarize this aspect. (shrink)

A simple model of an exciton-phonon system is studied in connection with quantum chaos.

A generalization of Weinberg’s nonlinear quantum theory is used to model a reported violation of the predictions of orthodox quantum theory.

The main question addressed in this essay is whether quarks have been observed in any sense and, if so, what might be meant by this use of the term, observation. In the first (or introductory) section of the paper, I explain that well-known researchers are divided on the answers to these important questions. In the second section, I investigate microphysical observation in general. Here I argue that Wilson's analogy between observation by means of high-energy accelerators and observation by means of (...) microscopes is misleading, for at least three reasons. Moreover, so long as high-energy observation is accomplished by means of spark or bubble chambers, then sentences about these observations do not meet Maxwell's criterion, that observation statements are quickly decidable. I argue, however, that this criterion is not a good norm for what is observable in high-energy physics, both because it would result in our describing a great many allegedly observed particle events as unobserved or theoretical, and because it fails to distinguish the reasons why some observation statements might not be quickly decidable. Most important, Maxwell's criterion fails because, contrary to Hanson's analysis, it presupposes that seeing does not involve both seeing as and seeing that.With this background concerning what is meant by general microphysical observation, in the third section of the essay, I discuss what might be meant by a more particular type of observation, that of the quark via scattering events. I employ Feinberg's distinction concerning observation of manifest, versus existent, particles and claim that the alleged indirect observation of quarks as existent particles is really based on a retroductive inference. I explain which premise in the retroductive argument appears most open to the charge of being theoretical (in a damaging sense) and less substantiated by observation. (shrink)

Recent authors have raised objections to the counterfactual interpretation of the Aharonov-Bergmann-Lebowitz rule of time-symmetrised quantum theory. I distinguish between two different readings of the ABL rule, counterfactual and non-counterfactual, and confirm that TSQT advocate L. Vaidman is employing the counterfactual reading to which these authors object. Vaidman has responded to the objections by proposing a new kind of time-symmetrised counterfactual, which he has defined in two different ways. It is argued that neither definition succeeds in overcoming the objections, except (...) in a limited special case previously noted by Cohen and Hiley. In addition, a connection is made between TSQT and Price's concept of 'advanced action', which further supports the special case discussed. (shrink)

The assertion by Simmons and Park that the dynamical map associated with the Bloch equations of nuclear magnetic resonance is not completely positive is wrong.

In a recent essay, Quentin Smith revisits a question of philosophical cosmology. Why does the universe exist? This is one way of asking the existence question EQ. Smith notes that all theistic philosophical cosmologists have answered this question in terms of God’s creative choice. Smith favors an “atheistic” philosophical answer: “The universe exists because it has an unconditional probability of existing based on a fundamental law of nature.” He further declares: “This law of nature... is inconsistent with theism and implies (...) that God does not exist.” The structure of Smith's reasoning in defense of these claims is the following: The answer to EQ of theistic philosophical cosmologists is logically inconsistent with the answer of atheistic philosophical cosmologists. Therefore, theistic and atheistic philosophical cosmologies are logically inconsistent with each other. The atheistic answer to EQ is a complete answer to EQ. Therefore, theism is demonstrably false. I shall argue that Smith’s reasoning in defense of is not sound. From that, it follows that is not a proven truth. Assumption is controversial, and in the present context question-begging. It presupposes that materialism is true. Therefore, is not a proven truth. (shrink)

Having known classical wave optics and wave mechanics, can we reverse Schrödinger's path and extend the concept of families of rays of light to provide a new exact rendering of quantum optics including the Bose nature of photons? This question is answered in the affirmative, and the implications of the Bose symmetry for certain nonlocal correlations of the many-ray distribution functions are worked out. The similarities and the differences between classical and quantum wave optics are brought out. The ray-ray Bose (...) correlation is analyzed. The generating functional for the many-ray distribution functions is formulated; and the notion of paraxial illumination for quantum optics is made precise. (shrink)

It is an experimental fact that \ -decays produce in a cloud chamber at most one track and that this track points in a random direction. This seems to contradict the description of decay in Quantum Mechanics: according to Gamow a spherical wave is produced and moves radially according to Schrödinger’s equation. It is as if the interaction with the supersaturated vapor turned the wave into a particle. The aim of this note is to place this effect in the context (...) of Schrödinger’s Quantum Mechanics. We shall see that the properties of the initial wave function suggest the introduction of a semiclassical formalism in which the \ -wave can be described as a collection of semiclassical wavelets; each of them interacts with an atom and forms an entangled state. The interaction can be regarded as a semiclassical inelastic scattering event. The measurement selects the wave function of one of the ions, with a probability given by Born’s rule. This ion interacts with the atoms nearby leading to the formation of a droplet. One can reasonably assume that also the wavelet entangled with the selected ion has probability one to remain as part of the description of the system. The measurement process is therefore represented by a unitary operator. The wavelet remains sharply localized on a classical path \ It is still a probability wave: it determines the probability that another atom be ionized. This probability is essentially zero unless the atom lies on \ . This gives the visible track. (shrink)

In this note a recently developed quantum oscillating finite space cosmological model is described. The principle novelty of the model is that there is a quantum blurring of the classical singularity between cycles, instead of a singularity free bounce. Recently, Quentin Smith (1988) has argued that present theoretical and observational evidence justifies the belief that the past history of the universe is finite. The relevance of this cosmological model to Smith's arguments is discussed.

A universal, unified theory of transformations of physical systems based on the propositions of probabilistic physics is developed. This is applied to the treatment of decay processes and intramolecular rearrangements. Some general features of decay processes are elucidated. A critical analysis of the conventional quantum theories of decay and of Slater's quantum theory of intramolecular rearrangements is given. It is explained why, despite the incorrectness of the decay theories in principle, they can give correct estimations of decay rate constants. The (...) reasons for the validity of the Arrhenius formula for the temperature dependence of an intramolecular rearrangement rate constant are discussed. A criterion for the possibility of a proper intramolecular rearrangement is given. The issue of causality in quantum physics is settled. (shrink)

Quantum optics does not give a local explanation of the coincidence counts in spatially separated photodetectors. This is the case for a wide variety of phenomena, including the anticorrelated counting rates in the two channels of a beam splitter, the coincident counting rates of the two “photons” in an atomic cascade, and the “antibunching” observed in resonance fluorescence.We propose a local realist theory that explains all of these data in a consistent manner. The theory uses a completely classical description of (...) the electromagnetic field, but with boundary conditions of the far field that are equivalent to assuming a real fluctuating, zero-point field. It is related to stochastic electrodynamics similarly to the way classical optics is related to classical electromagnetic theory.The quantitative aspects of the theory are developed sufficiently to show that there is agreement with all experiments performed till now. (shrink)

In a recent Analysis article, Quentin Smith argues that classical theism is inconsistent with certain consequences of Stephen Hawking's quantum cosmology.1 Although I am not a theist, it seems to me that Smith's argument fails to establish its conclusion. The purpose of this paper is to show what is wrong with Smith's argument. According to Smith, Hawking's cosmological theory includes what Smith calls "Hawking's wave function law." Hawking's wave function law (hereafter, "HL") apparently has, among its consequences, the following claim. (...) (1) The unconditional probability that a universe like this one - i.e., a universe with the metric hij and matter field Φ - should begin to exist is 95%.2 Smith then argues that the theist who accepts HL must also accept that the following sentence was once true.3.. (shrink)

The arguments that are often put forward to justify the singular importance given to completely positive maps over more generic maps in describing open quantum evolution are studied. We find that these do not appear convincing on closer examination. Positive as well as not positive maps are good candidates for describing open quantum evolution.

This paper puts forward the problem of singularity – one of the most important issues in contemporary cosmology. Firstly, the history of “singularity” concept and basis of Penrose’s and Hawking’s theorem of singularity are discussed. Secondly, the problem of singularity is presented as a genesis of search of quantum theories of the beginning of the Universe, in which the concept of singularity is not present. One sophisticated concept of Hartle and Hawking is presented, in particular the authors’ methodology is described. (...) The paper shows many possible philosophical problems which are connected with quantum cosmology. (shrink)

We review the problem of finding a general framework within which one can construct quantum theories of non-standard models for space, or space-time. The starting point is the observation that entities of this type can typically be regarded as objects in a category whose arrows are structure-preserving maps. This motivates investigating the general problem of quantising a system whose ‘configuration space’ (or history-theory analogue) is the set of objects Ob(Q) in a category Q. We develop a scheme based on constructing (...) an analogue of the group that is used in the canonical quantisation of a system whose configuration space is a manifold Q ≃ G/H, where G and H are Lie groups. In particular, we choose as the analogue of G the monoid of “arrow fields” on Q. Physically, this means that an arrow between two objects in the category is viewed as an analogue of momentum. After finding the ‘category quantisation monoid’, we show how suitable representations can be constructed using a bundle (or, more precisely, presheaf) of Hilbert spaces over Ob(Q). For the example of a category of finite sets, we construct an explicit representation structure of this type. (shrink)

The purpose of the simultaneous measurement of noncommuting quantum observables can be viewed as the joint estimation of parameters of the density operator of the quantum system. Joint estimation involves the application of a multiply parameterized operator-valued measure. An example related to the simultaneous estimation of the position and velocity of a particle is given. Conceptual difficulties attending simultaneous measurement of noncommuting observables are avoided by this formation.

The book is the first to give a systematic account, founded in fundamental quantum physical principles, of how the brain functions as a unified system.

There has been a long-standing and sometimes passionate debate between physicists over whether a dynamical framework for quantum systems should incorporate not completely positive (NCP) maps in addition to completely positive (CP) maps. Despite the reasonableness of the arguments for complete positivity, we argue that NCP maps should be allowed, with a qualification: these should be understood, not as reflecting ‘not completely positive’ evolution, but as linear extensions, to a system’s entire state space, of CP maps that are only partially (...) defined. Beyond the domain of definition of a partial-CP map, we argue, much may be permitted. (shrink)

The possibility of a sub-quantum mechanical realm has been investigated in recent years by DeBroglie, Bohm, Vigier, and others. It is felt that what is needed in this investigation is some simple and direct resolution of the problem as to whether sub-quantum entities exist or not. By restricting attention to quanta of light energy there is presented a theoretical expression for a sub-quantum or micro-photon which has proven to be testable. It is possible by this development to bridge the particle-wave (...) duality wherein these two conceptions become arithmetically commensurate with one another. The theoretical expression derived for the micro-photon also leads to a different interpretative approach to Planck's constant as well as the appearance of a new unit or element of mass. (shrink)